Lockable ball joints are useful in many different applications, such as camera supports, wheelchairs, tool holders, etc. One typical example of a lockable double ball joint is recognized as Manfrotto 155 double ball joint head, which is primarily used for a camera support. It comprises two plate shaped halves having recesses constituting ball seats. In order to lock the joint a screw is used to tighten the halves together. This joint is open at the sides thereby being vulnerable to dirt.
The present invention is in particular directed to appliance holders such as computer holders, and one application area of particular interest is vehicles. Today a driver of a vehicle often needs to bring a computer along in the vehicle, as a tool of labour of for private use. In order for the computer to be easily accessible it is convenient to have it mounted on a computer holder in the vehicle. Further, it is convenient that the computer holder is settable in different positions such that the computer can be moved into an operation position when the driver wants to use it and into a resting position when the driver is to start driving the vehicle. For that purpose computer holders comprising a lockable ball joint have been developed. However the computer holders existing on the market all suffer from being too week. The ball joint does not lock well enough to withstand the forces arising when a vehicle is driven on a bumpy ground.